U.S. patent application number 09/907988 was filed with the patent office on 2002-01-24 for thermal-assisted magnetic storage device and method for driving the reading/writing head thereof.
Invention is credited to Shimoda, Kazumasa, Uzumaki, Takuya.
Application Number | 20020008930 09/907988 |
Document ID | / |
Family ID | 18712939 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020008930 |
Kind Code |
A1 |
Shimoda, Kazumasa ; et
al. |
January 24, 2002 |
Thermal-assisted magnetic storage device and method for driving the
reading/writing head thereof
Abstract
[SUBJECT] To accomplish accurate alignment between a
reading/writing magnetic head and light-beam pickup of a
thermal-assisted magnetic storage device, and thereby to realize a
compact-size and higher capacity magnetic storage device without
reading/writing errors. [MEANS FOR SOLVING THE SUBJECT] In a
thermal-assisted magnetic storage device, for example, A
thermal-assisted magnetic storage device, comprising: a magnetic
recording media being comprised from transparent material; a first
marker of optically singular compared with materials therearound; a
magnetic head disposing on a magnetic head slider, being faced with
the recording surface of said magnetic recording media; a
light-beam pickup disposing on other surface of said magnetic
recording media, being at opposite side from said magnetic head, so
as to emit light therefrom to the surface of said magnetic
recording media, and thereby; alignment between said light and said
magnetic head is performed in accordance with detecting result of
reflective light reflecting from said first marker.
Inventors: |
Shimoda, Kazumasa; (Isehara,
JP) ; Uzumaki, Takuya; (Zama, JP) |
Correspondence
Address: |
GREER, BURNS & CRAIN
300 S WACKER DR
25TH FLOOR
CHICAGO
IL
60606
US
|
Family ID: |
18712939 |
Appl. No.: |
09/907988 |
Filed: |
July 18, 2001 |
Current U.S.
Class: |
360/59 ;
G9B/5 |
Current CPC
Class: |
G11B 5/012 20130101;
G11B 2005/0005 20130101; G11B 2005/0021 20130101; G11B 5/00
20130101 |
Class at
Publication: |
360/59 |
International
Class: |
G11B 005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 18, 2000 |
JP |
2000-217896 |
Claims
What is claimed is:
3. A thermal-assisted magnetic storage device, comprising: a
magnetic recording media being comprised from transparent material;
a first marker of optically singular compared with materials
therearound; a magnetic head disposing on a magnetic head slider,
being faced with the recording surface of said magnetic recording
media; a light-beam pickup disposing on other surface of said
magnetic recording media, being at opposite side from said magnetic
head, so as to emit light therefrom to the surface of said magnetic
recording media, and thereby; alignment between said light and said
magnetic head is performed in accordance with detecting result of
reflective light reflecting from said first marker.
4. The thermal-assisted magnetic storage device as claimed in claim
1, further comprising: a second marker, by whom light assists rough
movement to said first marker position, and disposing on said
magnetic head slider side.
5. The thermal-assisted magnetic storage device as claimed in claim
2, wherein said second marker is arranged in the direction which
becomes a standard where light moves, and so that said first marker
is arranged straight in the extension.
6. The thermal-assisted magnetic storage device as claimed in claim
2, wherein said second marker is comprised from: a first line part
so that the first above-mentioned marker is arranged in one
direction which becomes a moving standard in straight and the
extension; and a second line part being the plural in a direction
orthogonal for above one side according to the interval with a
predetermined order.
7. The thermal-assisted magnetic storage device as claimed in claim
4, wherein each of plural of said line parts are arranged at equal
intervals.
8. The thermal-assisted magnetic storage device as claimed in claim
4, wherein the intervals between the plural of said second line
parts are shortened gradually at fixed rate each other in
accordance with distance to said first line part.
9. The thermal-assisted magnetic storage device as claimed in
claims 4 through 6, wherein at least one of said first and second
lines are comprised from dotted line.
10. The thermal-assisted magnetic storage device as claimed in
claim 2, wherein the second marker of said first line part is as
said first marker is arranged in one direction which becomes a
moving standard in straight and the extension.
11. The thermal-assisted magnetic storage device as claimed in
claim 8, wherein said first line part is comprised from a dotted
line.
12. The thermal-assisted magnetic storage device as claimed in
claims 4 through 7, wherein said second line part is comprised from
zigzag with predetermined cycle which gradually increases or
gradually decreases.
13. The thermal-assisted magnetic storage device as claimed in
claim 10, wherein said cycle is continued from end to end of said
second line part.
14. The thermal-assisted magnetic storage device as claimed in
claim 9, wherein the length of the solid line part of dotted lines
among said first line part spreads at a fixed rate in accordance
with distance from said first marker.
15. The thermal-assisted magnetic storage device as claimed in
claims 8 through 12, wherein the interval between said first line
part spreads in accordance with distance from said first
marker.
16. The thermal-assisted magnetic storage device as claimed in
claims 1 through 13, wherein at least one of said first and second
marker is comprised from at least one element selected from a group
of Al (Aluminum), Ag (Silver), and Pt (Platinum), and thereby it
has higher reflexibility compared with surroundings.
17. The thermal-assisted magnetic storage device as claimed in
claims 1 through 13, wherein at least one of said first and second
marker is comprised from a roughness on said magnetic head
slider.
18. The thermal-assisted magnetic storage device as claimed in
claim 15, wherein said first and second marker is comprised from a
convex part formed heating it by high-energy line irradiation.
19. A method for driving reading/writing head of a thermal-assisted
magnetic storage device, comprising the steps of: the position
matches and has the marker who becomes aim. On the other hand,
readout and the writing method of driving the head of the optical
assistance magnetism record device to which the above-mentioned
position match is induced with the marker for the rough movement
installed so that the reflection of the above-mentioned light
become speculiar when the light irradiated from an optical picking
up is matched the position.
18. The method for driving reading/writing head of a
thermal-assisted magnetic storage device as claimed in claim 17,
wherein said rough guiding marker forms straight, and a marker as a
target for said alignment is located in the extension.
19. The method for driving reading/writing head of a
thermal-assisted magnetic storage device as claimed in claim 17,
wherein said rough guiding marker is comprised from plural straight
pattern, which comprises the rib portion where plural straight
parts are composed in parallel in the extension the composition of
plural straight markers the match and installing the marker who
becomes aim, and going directly.
20. The method for driving reading/writing head of a
thermal-assisted magnetic storage device as claimed in claim 19,
further comprising the steps of: a step of detecting said rib
portion by scanning in the direction which first intersects with
said rib portion, after light-beam irradiates to said magnetic head
slider side; and a step of detecting said backbone portion by
scanning in a parallel direction to said rib portion.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims priority of
Japanese Patent Application No. 2000-217896, filed, the contents
being incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a magnetic storage device
technology, which has been broadly applied to several hardware,
e.g., personal computers and workstations, in information
technologies field. In detail, the present invention relates
especially to a thermal-assisted (or light-assisted) magnetic
storage device technology to realize gigantic memory capacity
without enlarging its current physical size.
[0004] Nowadays, acceleration of the information technologies
demands higher memory capacity and smaller physical size for
magnetic storage device, and thereby it is highly demanded that a
reliable data reading technology for realizing to accurately read
data without errors even from tiny field on very high density
storage media surface. According to such technical background,
thermal-assisted magnetic storage device has been appeared, and it
is to improve magnetic storage media's coercive force through a
thermal assist data writing accompanied by focused light beam.
Namely, when writing data on the magnetic storage media, the
magnetic storage media surface to be written a datum is thermally
annealed and thereby the coercive force of the data-writing portion
on the magnetic storage media surface becomes lower compared with
prior to the thermally annealing. The present invention relates to
an improvement for realizing accurate alignment between the
magnetic write head and a light-beam pickup in the thermal-assisted
magnetic storage device, which the magnetic write head and the
light-beam pickup are disposed at both sides of one magnetic
storage disc media.
[0005] 2. Discussion of the Related Art
[0006] As exemplified in FIG. 1, the thermal-assisted magnetic
storage device employs a magnetic storage disc as a magnetic
storage media and a magnetic head to which the surface of the
magnetic storage disc is adjacent, and thereby a magnetic sensor
formed on the magnetic head is capable of reading storage data as
magnetic information on the surface of the magnetic storage disc.
And further, the light-beam is led to the magnetic head through
fine glass fiber along with holding spring for holding the magnetic
head, and thereby the light-beam can arrive at the magnetic disc
substrate surface. Through such structure as in the above, tiny
spot on the magnetic disc surface can be partially heated up by
exposing to the light-beam. Such thermal-assisted magnetic storage
device has been proposed.
[0007] However, such technique as in the above can be hardly
applied to the high-density magnetic recording storage device
although it might be applied to conventional level low-density
magnetic storage device. That is to say, in conventional technology
situation, no serious problem could be raised, because width of one
magnetic recorded data occupied field, i.e., so-called
`Tracking-pitch`, is much larger compared with a distance between
the magnetic sensor and the light-beam spot although the end
portion of the glass fiber is disposed to the magnetic head. On the
other hand, in much higher density magnetic storage device
technology, as the tracking-pitch becomes to be smaller than the
distance between the magnetic sensor and the light-beam spot, the
magnetic recording disc surface itself can be hardly heated up by
exposing the light-beam. As a result of this problem, the
thermal-assistance function of the thermal-assisted magnetic
storage device will not be able to fully obtain desired effect.
Thus, in case that the thermal-assistance function is applied to
such higher density magnetic storage device, the thermal-assistance
function might make no sense.
[0008] In such circumstances, another technology is demanded. The
magnetic recording disc itself is comprised from transparent
material, and light-beam spot is emitted from different side of
such transparent magnetic recording disc from the side of the
magnetic head. However, because the slider surface of the magnetic
head is highly integrated and very small as the same level as
cutting edge semiconductor device, light-beam spot can be difficult
to align to such very small magnetic sensor.
SUMMARY OF THE INVENTION
[0009] As stated in the above, because such high-density recording
technology is demanded, the light-beam spot itself also becomes to
be downsized to tiny size, such as sub-micron order. And further,
the magnetic sensor, which is disposed on the slider surface of the
magnetic head, also becomes to be downsized to tiny size as the
same level. If the magnetic sensor and the light-beam spot are not
aligned even a bit with each other when data reading operation,
recorded data is undesirably rewritten and therefore recording data
error cannot be inevitably occurred. Therefore, the alignment
technologies, which can be realize quick and accurate alignment
between the magnetic sensor and the light-beam spot, is found as
the problem to be improved in the related art.
[0010] As a solution against such related art's problem, each of
following means, for instance, will be applied according to the
present invention.
[0011] (1) A thermal-assisted magnetic storage device,
comprising:
[0012] a magnetic recording media being comprised from transparent
material;
[0013] a first marker of optically singular compared with materials
therearound;
[0014] a magnetic head disposing on a magnetic head slider, being
faced with the recording surface of said magnetic recording
media;
[0015] a light-beam pickup disposing on other surface of said
magnetic recording media, being at opposite side from said magnetic
head, so as to emit light therefrom to the surface of said magnetic
recording media, and thereby;
[0016] alignment between said light and said magnetic head is
performed in accordance with detecting result of reflective light
reflecting from said first marker.
[0017] (2) The thermal-assisted magnetic storage device as in (1)
further comprising:
[0018] a second marker, by whom light assists rough movement to
said first marker position, and disposing on said magnetic head
slider side.
[0019] (3) The thermal-assisted magnetic storage device as in (2)
wherein said second marker is arranged in the direction which
becomes a standard where light moves, and so that said first marker
is arranged straight in the extension.
[0020] (4) The thermal-assisted magnetic storage device as in (2)
wherein said second marker is comprised from:
[0021] a first line part so that the first above-mentioned marker
is arranged in one direction which becomes a moving standard in
straight and the extension; and
[0022] a second line part being the plural in a direction
orthogonal for above one side according to the interval with a
predetermined order.
[0023] (5) The thermal-assisted magnetic storage device as in (4)
wherein each of plural of said line parts are arranged at equal
intervals.
[0024] (6) The thermal-assisted magnetic storage device as in (4)
wherein the intervals between the plural of said second line parts
are shortened gradually at fixed rate each other in accordance with
distance to said first line part.
[0025] (7) The thermal-assisted magnetic storage device as in (4)
through (6), wherein at least one of said first and second lines
are comprised from dotted line.
[0026] (8) The thermal-assisted magnetic storage device as in (2),
wherein the second marker of said first line part is as said first
marker is arranged in one direction which becomes a moving standard
in straight and the extension.
[0027] (9) The thermal-assisted magnetic storage device as in (8)
wherein said first line part is comprised from a dotted line.
[0028] (10) The thermal-assisted magnetic storage device as in (4)
through (7), wherein said second line part is comprised from zigzag
with predetermined cycle which gradually increases or gradually
decreases.
[0029] (11) The thermal-assisted magnetic storage device as in (10)
wherein said cycle is continued from end to end of said second line
part.
[0030] (12) The thermal-assisted magnetic storage device as in (9)
wherein the length of the solid line part of dotted lines among
said first line part spreads at a fixed rate in accordance with
distance from said first marker.
[0031] (13) The thermal-assisted magnetic storage device as in (8)
through (12), wherein the interval between said first line part
spreads in accordance with distance from said first marker.
[0032] (14) The thermal-assisted magnetic storage device as in (1)
through (13), wherein at least one of said first and second marker
is comprised from at least one element selected from a group of Al
(Aluminum), Ag (Silver), and Pt (Platinum), and thereby it has
higher reflexibility compared with surroundings.
[0033] (15) The thermal-assisted magnetic storage device as in (1)
through (13), wherein at least one of said first and second marker
is comprised from a roughness on said magnetic head slider.
[0034] (16) The thermal-assisted magnetic storage device as in
(15), wherein said first and second marker is comprised from a
convex part formed heating it by high-energy line irradiation.
[0035] (17) A method for driving reading/writing head of a
thermal-assisted magnetic storage device, comprising the steps
of:
[0036] the position matches and has the marker who becomes aim. On
the other hand, readout and the writing method of driving the head
of the optical assistance magnetism record device to which the
above-mentioned position match is induced with the marker for the
rough movement installed so that the reflection of the
above-mentioned light becomes peculiar when the light irradiated
from an optical picking up is matched the position.
[0037] (18) The method for driving reading/writing head of a
thermal-assisted magnetic storage device as in (17), wherein said
rough guiding marker forms straight, and a marker as a target for
said alignment is located in the extension.
[0038] (19) The method for driving reading/writing head of a
thermal-assisted magnetic storage device as in (17), wherein said
rough guiding marker is comprised from plural straight pattern,
which comprises the rib portion where plural straight parts are
composed in parallel in the extension the composition of plural
straight markers the match and installing the marker who becomes
aim, and going directly.
[0039] (20) The method for driving reading/writing head of a
thermal-assisted magnetic storage device as in (19), further
comprising the steps of:
[0040] a step of detecting said rib portion by scanning in the
direction which first intersects with said rib portion, after
light-beam irradiates to said magnetic head slider side; and a step
of detecting said backbone portion by scanning in a parallel
direction to said rib portion.
[0041] Namely, the present invention is intended to propose
following means to solve aforementioned related art's problem.
According to the present invention, optically singular marker is
formed adjacent to the magnetic sensor of the magnetic head for
reading recorded data, and light-beam spot can be aligned to the
marker without delay. In detail, the optical marker can be
comprised from (a) thin film of optically singular reflection
index, or (b) pattern of significant roughness. As an example of
(a) above, thin metal film of higher reflection index compared with
slider surface, e.g., Al (Aluminum), Pt (Platinum), Ag (Silver),
can be employed. And also, as an example of (b) above, either an
etched ditch though a method of e.g., FIB (Focused Ion Beam) or RIE
(Reactive Ion Etching) or a laser bump through thermally melting by
high power laser can be employed.
[0042] The light detecting element such as photo diodes is
installed in the optical picking up set up at the position where
the receiving light of the reflection light on the magnetic head
slider side can be done, and the change in reflection light
strength can be monitored by this light detecting element. Focus
adjusting is performed by driving object lens based on this
strength change. The position of an optical spot can be matched to
the marker by reading the change in reflection light strength by
the resolution of a submicron order by adopting the above-mentioned
marker, and when recording, the heating of the record part in the
medium becomes possible stably.
[0043] [Effect of the Invention]
[0044] A more certain, minuter, more magnetic record by the optical
assistance method can be realized to a simple optical assistance
magnetism record device which does not do the tracking based upon
the technology though it composes so far by the cancellation's of
weakening and the output decrease in record information which
becomes a problem becoming possible according to this invention. An
enough reproduction output can be obtained, and the reproduction's
recording and operating become possible stably consequently the
hard disk drive of super high recording density because the record
part in the medium can be stably heated up when recording by using
the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] FIG. 1: Plan view (Enlarged plan view of a main portion) of
the magnetic head of the thermal-assisted magnetic storage device,
according to the first embodiment of the present invention
[0046] FIG. 2: Plan view of the magnetic head of the
thermal-assisted magnetic storage device, according to the first
embodiment of the present invention
[0047] FIG. 3: Structural view of the thermal-assisted magnetic
storage device according to the first embodiment of the present
invention
[0048] FIG. 4: Cross-sectional view of the magnetic head slider
(reflective index differentiation type marker) according to the
first embodiment of the present invention
[0049] FIG. 5: Cross-sectional view of the magnetic head slider
(bump pattern type marker) according to the second embodiment of
the present invention
[0050] FIG. 6: Cross-sectional view of the magnetic head slider
(Laser Bump type marker) according to the third embodiment of the
present invention
[0051] FIG. 7: Tracking profile (No. 1) of the output in case of
reading data according to the related art
[0052] FIG. 8: Tracking profile (No. 2) of the output in case of
reading data according to the related art
[0053] FIG. 9: Tracking profile (No. 1) of the output in case of
reading data according to the first embodiment of the present
invention
[0054] FIG. 10: Tracking profile (No. 2) of the output in case of
reading data according to the first embodiment of the present
invention
[0055] FIG. 11: The explanatory figure of the alignment steps
according to the first embodiment of the present invention
(Enlarged plan view of the magnetic head slider)
[0056] FIG. 12: The explanatory figure of the first modification of
the embodiment (Enlarged plan view of the magnetic head slider)
[0057] FIG. 13: The explanatory figure of the second modification
of the embodiment (Enlarged plan view of the magnetic head
slider)
[0058] FIG. 14: The explanatory figure of the third modification of
the embodiment (Enlarged plan view of the magnetic head slider)
[0059] FIG. 15: The explanatory figure of the fourth modification
of the embodiment (Enlarged plan view of the magnetic head
slider)
[0060] FIG. 16: The explanatory figure of the fifth modification of
the embodiment (Enlarged plan view of the magnetic head slider)
[0061] FIG. 17: The explanatory figure of the sixth modification of
the embodiment (Enlarged plan view of the magnetic head slider)
[0062] FIG. 18: The explanatory figure of the seventh modification
of the embodiment (Enlarged plan view of the magnetic head
slider)
[0063] FIG. 19: The explanatory figure of the eighth modification
of the embodiment (Enlarged plan view of the magnetic head
slider)
DETAILED DESCRIPTION
[0064] Reference is now made in detail to specific embodiments of
the present invention that illustrates the best mode presently
contemplated by the inventors for practicing the invention.
[0065] [First Embodiment]
[0066] FIG. 1 is a plan view figure (Enlarged plan view of a main
portion) of the magnetic head of the thermal-assisted magnetic
storage device, according to the first embodiment of the present
invention. FIG. 2 is a plan view figure of the magnetic head of the
thermal-assisted magnetic storage device, according to the present
invention. And further, FIG. 3 is a structural view figure of the
thermal-assisted magnetic storage device according to the first
embodiment of the present invention. Referring to these figures,
the first embodiment of the present invention will be explained
hereinbelow.
[0067] Referring to FIGS. 1 through 3:
[0068] The magnetic head surface, which is faced to the disc
surface, is as illustrated in FIG. 1. And also, the magnetic head
comprises the magnetic head slider, which is only 1.2 mm long and
thereby has very tiny surface structure, as illustrated in FIG. 3.
And also, the magnetic head, which is connected to an arm, can be
floated just a bit above the magnetic disc, which rotates very
speedy so as to generate tiny swirls enough to make the magnetic
head float, and thereby the floating magnetic head can read data
recorded on the magnetic storage disc. However, the magnetic head
employing actual data reading from magnetic disc surface is only a
small portion of the surface, as illustrated in FIG. 3. If
enlarged, it has a structure as illustrated in FIG. 2. The magnetic
head is formed in a small area of no more than approx. 200 .mu.m
width, as in the FIG. 2, and also a data reading element is formed
likely as fine pattern located in a portion of such small area.
[0069] The alignment, which is the object of the present invention,
shall be performed so as to align to the data-reading element,
which is a fine pattern in a very small area. Meanwhile, light-beam
spot, e.g., laser spot, should not directly expose to the data
reading element. This is because high energy of the laser spot
might be degraded even in case of short time exposure. Thus, the
optically singular marker is set aside a portion adjacent to the
data reading element and is used as a target of alignment, and
thereby laser spot's long-time direct exposure to the data reading
element can be avoidable.
[0070] Referring to FIG. 4:
[0071] FIG. 4 is a cross-sectional view figure of the magnetic head
slider (reflective index differentiation type marker) according to
the first embodiment of the present invention. In this embodiment,
although the magnetic head slider surface is commonly comprised
from metal material, the optical marker 2 can be comprised from
some glitter material, which can be reflective index can be
significantly high, e.g., vapor-deposited metal such as aluminum or
gold. The formation of the optical marker is, for instance, as
follows. First, a photoresist film is formed on the surface of the
magnetic head slider, and a window opening in desired portion is
patterned through a known photolithographic method. After that, dry
etching is applied by using the patterned photoresist film as a
mask so as to an etched ditch in the magnetic head slider surface.
And further, aluminum is deposited through a conventional
sputtering on the whole surface of the magnetic head slider
including the etched ditch. Moreover, aluminum on the outer surface
of the etched ditch on the magnetic head slider surface is etched
back through CMP (chemical Mechanical Polishing) technique so as
not to etch aluminum from the etched ditch, and thereby the optical
marker 2 as illustrated in FIG. 4.
[0072] Referring again to FIG. 2:
[0073] Referring again to FIG. 2, plan view figure of the magnetic
head of the thermal-assisted magnetic storage device, according to
the first embodiment of the present invention, the structural
feature of the magnetic head will be explained hereinafter. It is
difficult and ineffective to search for the location of the
optically singular marker 2, which is to be a target of the light
alignment and is formed adjacent to the data reading element 1,
without any guidance. Due to lack of guidance, it will take a long
time to recognize accurate location of the optically singular
marker 2. Thus, according to the present invention, a rough guiding
marker 3, which is also optically singular compared to the magnetic
head surface, is employed so as to lead the light-beam spot to the
marker 2. When the light-beam spot scans on the surface of the
magnetic head slider, the light-beam spot will be moved toward
basically two directions, i.e., x-axis direction and y-axis
direction falling at right angles with the x-axis. In such ways, if
plural rough guiding markers 3 of fine line shape are disposed so
as to be in parallel with the direction of moving the light beam,
it will become to easily recognize as to whether the marker 2 is
far from the location of the light-beam spot or the marker 2 is
close to the location. Thus, the light-beam spot can be led to the
marker 2 without any misleading or without going lost its way.
[0074] The steps for introducing the light-beam spot to the marker
2 is exemplified in detail hereinbelow.
[0075] Referring to FIG. 11:
[0076] FIG. 11 is the explanatory figure of the alignment steps
according to the first embodiment of the present invention
(Enlarged plan view of the magnetic head slider). In the FIG. 11,
the rough guiding marker 3 is comprised from a backbone portion 3a
leading to the marker 2 and plural rib portions 3b disposing so as
to fall at right angles with the backbone portion 3a. For instance,
supposing the situation that the light-beam spot is located first
at a location A in the FIG. 11, reflection from the location A is
not so significantly detected, and thereby it is understood that
any marker is not located at the location A. After that, the
light-beam spot is going to try moving upwardly or downwardly. In
this step, if the light-beam spot is moved upwardly, then the light
reflection becomes most significant at a location B in the FIG. 11,
and thereby it is understood that a sort of marker is located at
the location B. On the other hand, if the light-beam spot is moved
downwardly, then the light reflection becomes most significant also
at a location C in the same FIG. 11, and thereby it is understood
that a sort of marker is located at the location C. The algorithm,
which has been so far explained, can lead us to recognize the
location A is disposed between two rib portions 3b, which are
neighbor with each other.
[0077] And the next, the light-beam spot is moved toward the
different direction falling at right angles with the direction in
the above. Namely, the light-beam spot scans in a right and left
direction on the FIG. 11. In the same manner as explained in the
above, light reflection is maximized at a location D, and thereby
the backbone 3b can be recognized on the location D. And also, if
the light-beam spot scans up and down, then light-beam spot can be
arrived at the marker 2 location. Through the above steps, the
light-beam spot is accurately aligned to the marker 2.
[0078] In the above embodiment, the rough guiding marker 3 is
thought to have several modifications. But, as far as two direction
scanning of the light-beam spot, the rough guiding marker 3 is
simple but effective if it is comprised from a first line pattern
e.g., the backbone portion, elongating to the marker 2 or adjacent
to the marker 2 and a second line pattern, e.g., the rib portion,
disposing so as to fall at right angles with the first line
pattern.
[0079] Referring again to FIG. 1:
[0080] FIG. 1 is a plan view figure (Enlarged plan view figure of a
main portion) of the magnetic head of the thermal-assisted magnetic
storage device, according to the first embodiment of the present
invention. In the FIG. 1, a disc 5 is comprised from transparent
material enough to make the light-beam pass therethrough. A very
thin magnetic material covers on the disc 5 surface, as a magnetic
recording layer 51. The magnetic head 6 is floated just a bit above
the rotating disc 5 by small swirls, which is generated by
high-speed rotation, and the floating magnetic head 6 can read data
from the magnetic recording layer 51. On the other hand, light-beam
pickup 7 is disposed on the opposite side of the disc 5, and the
light-beam can pass through the transparent disc 5, and thereby it
can be aligned to the magnetic head 6. And also, at the same time,
it can partially heat up the temperature of the tiny area. Due to
the necessity of light-beam exposure in tiny area, coherent laser
is favorably applied to the light-beam spot.
[0081] Details of the light-beam pickup 7 is as follows. When the
light-beam pickup 7 scans, alteration in refection intensity can be
recognized. Corresponding to the alteration in refection intensity,
FE Signal (Focus Error Signal) is generated. And also, according to
the FE Signal, first target is the rough guiding marker (not shown
in the figure) on the magnetic head slider surface 61. In
accordance with aforementioned algorithm, light-beam scanning will
be continued and tracking any marker by driving field lens and
referring to alteration in the FE Signal (Focus Error Signal). In
more detail, when the system can recognize the alteration in
reflection intensity by driving the light-beam pickup 7, FE Signal
(Focus Error Signal) will be generated in accordance with the
recognition. After the FE Signal (Focus Error Signal) is amplified
by amplifier, it is transferred to a servo circuit. The signal is
also provided to a control circuit, and thereby an x-y-z stage is
moved, if required, by driving the servo circuit so as to promote a
bit vibrating the light-beam pickup on a goniometer.
Simultaneously, the control circuit outputs a signal to a Laser
Diode (LD) activation circuit only when data writing, and
thereafter a LD signal (Laser Diode signal), which is output by the
LD activation circuit, is transferred to the light-beam pickup to
light the Laser Diode, and thereby a desired spot on the magnetic
recording layer 51 surface is heated up.
[0082] Referring to FIGS. 7 through 10:
[0083] FIG. 7 shows a tracking profile (No. 1) of the output in
case of reading data according to the related art, and it
illustrates the output's tracking profile, which is observed just
after the alignment is completed, without applying the present
invention. And also, FIG. 8 shows a tracking profile (No. 2) of the
output in case of reading data according to the related art, and it
illustrates the output's tracking profile, which is observed one
hour after the alignment is completed, without applying the present
invention. And further, FIG. 9 shows a tracking profile (No. 1) of
the output in case of reading data according to the first
embodiment of the present invention, and it is observed just after
the alignment is completed. Similarly, FIG. 10 shows a tracking
profile (No. 2) of the output in case of reading data according to
the first embodiment of the present invention, and it is observed
one hour after the alignment is completed. In each of FIGS. 7
through 10, differential in location from the center of the
recording portion is scaled on its abscissa, and signal intensity
(m V) is scaled on its ordinate. And thereby, each of these figures
illustrates alteration in signal intensity in accordance with
differential in location.
[0084] Comparing between FIG. 9 illustrating the present
invention's tracking profile and FIG. 7 illustrating the related
art's tracking profile, both of these tracking profiles are the
same with each other. These figures teach that both tracking
profiles are not different from each other at the time just after
the alignment. However, comparing between FIG. 10 illustrating the
present invention's tracking profile at one hour later and FIG. 8
illustrating the present invention's tracking profile at one hour
later, both of these tracking profiles are significantly different
from each other. Namely, according to the related art of FIG. 8,
the intensity of the recorded data disposing adjacent to newly
recorded datum becomes to be pretty much degraded at one hour after
the data recording. On the other hand, according to the present
invention of FIG. 10, the intensity of the recorded data is not
weakened even at one hour after the data recording.
[0085] Now, other embodiments of the present invention will be
explained hereinafter in this sequence in detail, and each of
following embodiments discloses particularly regarding markers
structure on the magnetic head slider surface but other features
may be omitted because those are basically the same as
aforementioned first embodiment.
[0086] [Second Embodiment]
[0087] Referring to FIG. 5:
[0088] As a new marker structure being different from the first
embodiment so far explained, roughness pattern can also be applied
to the maker 2 portion, instead of the above-exemplified metal
film, e.g., aluminum film. FIG. 5 is a cross-sectional view figure
of the magnetic head slider (bump pattern type marker) according to
the second embodiment of the present invention. The method for
fabricating the above bump pattern type marker 2 is exemplified as
follows. For instance, the desired surface of the magnetic head
slider is a bit concaved through well-known dry etching method, and
thereby such concave can be used as the marker 2. Otherwise,
photoresist film is formed so as to cover the whole surface of the
magnetic head slider, and it is patterned through a known
photolithographic method so as to form the same shape as desired
marker 2, and thereafter, the magnetic head slider surface is
entirely etched back by using the photoresist pattern as a mask. As
a result of this etching back, marker 2 is patterned as a projected
area on the magnetic head slider surface. Except the marker 2
formation, the other entire feature fully takes over the first
embodiment. FIB (Focused ion Beam) method or RIE (Reactive Ion
Etching) method can be employed for the roughness formation above.
In case of RIE method, photoresist film covering on the magnetic
head slider is formed through spin-coating, and thereafter, known
photolithographic method using the photoresist as a mask is
applied, and thereafter, the exposed surface of the magnetic head
slider is exposed to the RIE etchant and thereby the exposed
surface is etched through RIE method. After the RIE, the
photoresist mask is removed by known dry ashing method, e.g.,
O.sub.2 Plasma ashing method. In contrast to anisotropic roughness
marker pattern through the above steps, isotropic roughness marker
pattern can also realize the present invention. To form such
isotropic roughness marker pattern, wet etching is applied.
However, anisotropic-etched marker pattern is more favorable than
isotropic one, because high peak of reflection intensity will be
detected at vertical wall of the anisotropic-etched marker pattern
and such vertical wall cannot form through isotropic etching
method.
[0089] [Third Embodiment]
[0090] Referring to FIG. 6:
[0091] As the third embodiment, laser bump marker pattern, which is
formed through laser melting, will be exemplified in detail
hereinbelow. FIG. 6 is a cross-sectional view figure of the
magnetic head slider (Laser Bump type marker) according to the
third embodiment of the present invention. As depicted in the FIG.
6, the Laser Bump type marker is formed through following method. A
laser spot is exposed selectively to a desired fine area (e.g., 0.5
.mu.m width) in the plan surface of the magnetic head slider, and
thereby the fine area is heated up and melted to form a roughness
marker. The above laser method can be effective with respect to
easiness of the marker formation.
[0092] The present invention has been explained so far by
exemplifying each of first, second, and third embodiments. And
further, several modifications are thought to be applicable to the
present invention, and therefore those modifications will be
disclosed hereinafter.
[0093] For instance, each of the rib portions of the rough guiding
marker is arranged in parallel and at even intervals in the
examples of FIGS. 2 and 11. Instead, each of the rib portions can
be also arranged in parallel and at different intervals. For
instance, closer to the optically singular marker, the shorter
interval is applied between two rib portions, which are neighbor
with each other. Such example will be explained, referring to FIG.
12, in below.
[0094] Referring to FIG. 12:
[0095] FIG. 12 is an explanatory figure of the first modification
of the embodiment (Enlarged plan view of the magnetic head slider).
Closer to the optically singular marker 2, the shorter intervals is
applied between one rib portion and its neighboring rib portion. In
other words, in accordance with distance from the optically
singular marker 2, each of the rib portions are arranged so as to
alter the interval distance. Such structure can be effective
regarding the easiness of approaching the optically singular
marker, because the system can recognize even by the interval
distance itself regarding how far the light-beam spot location is
from the optically singular marker as a target.
[0096] In FIG. 12, supposing the situation that the laser spot is
located in a location A, laser spot is moved first up and down from
the location A, and therethrough the rib portions can be found at
locations B and C, and the distance between B and C is calculated
and recognized as a interval between rib portions adjacent to the
current location of the laser spot. Through the above steps,
distance between the laser spot and the optically singular marker
in up and down direction can be roughly detected. As disclosed in
the above, if the laser spot is moved right and left from the
location A, then the backbone portion can be detected. And
thereafter, the laser spot can be jumped toward the optically
singular marker in one time in accordance with the aforementioned
distance calculation.
[0097] Referring to FIG. 13:
[0098] FIG. 13 is an explanatory figure of the second modification
of the embodiment (Enlarged plan view of the magnetic head slider).
This example sketches the rough guiding marker comprising dot lines
of reflexible material. Even in case of FIG. 13, laser spot
scanning steps are substantially the same as in FIG. 11. Namely,
the laser spot is first moved a bit up and down from the initial
location A, and therethrough the rib portions at locations B and C
can be detected. As a result of the above steps, the system can
recognize that the location A is disposed between two rib portions.
And thereafter, the laser spot is moved right and left from the
location A and thereby the backbone portion can be detected at a
location D. After that, the laser spot can be led up to the
optically singular marker 2 by the backbone portion. If the
arrangement of dots in the dotted line is gradually altered in
accordance with distance to the backbone, then the distance to the
optically singular marker 2 can be roughly detectable even only
through the up and down scanning from the initial position of the
laser spot. Moreover, it is also effective way to easily detect the
optically singular marker 2 that both the backbone portion and the
rib portions are comprised from dotted lines. In case of the dotted
backbone portion and the dotted rib portion, if each interval
between dots on the backbone and rib portions are changed in
accordance with the distance to the optically singular marker 2 or
to the backbone portion. This will be explained hereinafter.
[0099] Referring to FIG. 14:
[0100] FIG. 14 is an explanatory figure of the third modification
of the embodiment (Enlarged plan view of the magnetic head slider).
In accordance with the example of FIG. 14, the laser spot is first
moved up and down from its initial position A, and thus the rib
portions can be detected at each of the locations B and C, and
thereby the system can recognize that the initial position A is
disposed between the locations B and C. And the next, the laser
spot is moved right and left, and thus the backbone portion can be
detected at the location D. After that, the laser spot is led to
the optically singular marker 2 as a target along with the backbone
portion. Thus, all of the above steps are substantially the same as
in the first and second embodiments. However, if the laser spot is
just a bit moved right and left from the locations B and C, which
are intersected with the backbone portion, then the distance to the
rib portion can be recognized merely by calculating width of dotted
line nearest the laser spot.
[0101] In more details, when the laser spot is scanned for instance
right and left slightly at position B, the system recognizes the
distance between the dots on the dotted line. If it is short, then
the rib portion is near. On the other hand, if it is long, then the
rib portion is far located. There is accompanying effect of can
being able to measure the distance to the rib portion at a dash
when the distance is measured, tracing to the marker, and
shortening the process time until reaching the marker if it is
calculated as the distance between dotted lines of the rib portion
decreases gradually at a fixed rate toward the backbone.
[0102] Referring to FIG. 15:
[0103] FIG. 15 is an explanatory figure of the fourth modification
of the embodiment (Enlarged plan view of the magnetic head slider).
In the example of FIG. 15, one difference from the example of FIG.
14 is that only the backbone becomes like the dotted line. The
laser spot which lies to position A first is scanned as well as a
current example and the procedure brought close to the marker is
basically the same also in this example. Because the distance
between dotted lines can be detected when the surface of the
backbone is scanned after position D is detected, the thing to know
the distance to the marker at once can be done, and however, the
material of the marker and the backbone is especially long the
distance to the marker and when substance is finished up in
equivalence and the reflection condition is the same, very
advantageous for shortening the process time until the marker
position alignment.
[0104] In addition, it is also good to make the rib little zigzag
instead of consisting of the above-mentioned dotted line. It is
possible, as similarly as aforementioned, to search for the
backbone efficiently by knowing the distance to the backbone
becoming possible because it measures the distance between the
vicinity zigzag adjacent while scanning light if the cycle zigzag
is gradually made a short cycle in this situation as it approaches
the backbone at the center for instance effect is achieved. Such
example will be explained hereinafter, by referring to FIG. 16.
[0105] Referring to FIG. 16:
[0106] FIG. 16 is an explanatory figure of the fifth modification
of the embodiment (Enlarged plan view of the magnetic head slider).
The laser spot which lies to position A first scans vertically
first of all and searches for the intersection with the rib portion
where zigzag is done. It can be recognized that position A is
located between two rib portions that positions B and C are
detected thus. The laser spot is scanned from position A to the
right and left after this step. And thereafter, the laser spot is a
bit scanned right and left from the position A on the figure. In
this step, the laser spot have to scan over sufficiently long to
right and left compared with the zigzag cycle so as not to
misunderstand the zigzag of the rib portion as a part of the
backbone portion. According to this procedure, Position D is caught
after the scanning sufficiently long to right and left. The steps
traced to the optically singular marker after the above is
similarly in accordance with the above procedure.
[0107] In addition, if it wants to form the marker for a rough
movement by simpler process, all rib portions can be lost, and
rough guiding marker is comprised only from a backbone portion.
That is, it is possible to search for the marker by one respondent
by even forming only the marker for one rough movement by which the
marker who becomes the target of the position alignment is arranged
in parallel in the direction where light-beam is scanned. Moreover,
if the width of the backbone portion is narrowed as it gradually
approaches the optically singular marker, and the distance from the
width of the backbone portion to the optically singular marker is
made to be able to be measured, the formation achieves the effect
that it is possible to search for the marker by facilitating it
efficiently of the marker for a rough movement. This will be
explained based upon FIG. 17.
[0108] Referring to FIG. 17:
[0109] FIG. 17 is an explanatory figure of the sixth modification
of the embodiment (Enlarged plan view of the magnetic head slider).
The step by which the laser spot is aligned to the marker is as
follows. For instance, first of all, when the laser spot irradiates
it to position A first, only enough width scans the laser spot from
position A to the right and left. Thus, it can be recognized that
the backbone portion exists in position B where a large reflection
was obtained. Because there would be occurred the problem that the
laser spot unintentionally skips the backbone portion at no pattern
portion on dotted line part and therefore it does not recognize the
backbone portion, the interval between dot and dot on the backbone
portion should be narrower than the diameter of the laser spot. It
can be considerably narrow because it is sure to be able to be
recognized between dot and dot on the backbone pattern enough if
reflecting freely compared with the laser spot diameter.
[0110] Referring to FIG. 18:
[0111] FIG. 18 is an explanatory figure of the seventh modification
of the embodiment (Enlarged plan view of the magnetic head slider).
In this example, two rib portions are formed straight to extend
from the marker right and left as line symmetry, and the only
backbone portion is composed as a whole as a marker for a rough
movement. The laser spot which lies to position A is scanned to the
right and left very widely, and detects C, D, and B one by one
first of all at FIG. 18. Thus, it can be recognized that middle
point D is a backbone portion. At the same time, it can recognize
the distance from position D to the marker by referring to the
distances between C and D, and D and B. And thereby, position
alignment to the optically singular marker of the laser spot can be
easily and quickly completed in a short time. Easy and fast
approach to the optically singular marker is to be accomplished
even by this simple marker composition.
[0112] Referring to FIG. 19:
[0113] FIG. 19 is an explanatory figure of the eighth modification
of the embodiment (Enlarged plan view of the magnetic head slider).
In this example, the point to have made the function of the rib
portion in the backbone portion of this embodiment gradually become
wide as the backbone parted from the marker, and had feature. In
this example, first of all, if the laser spot breaks out first at
position A, it scans from position A to the right and left. Because
inflection point of reflectivity exists in B and C in this,
positions B and C can be considered to be an edge in the backbone
portion. In this situation, the thing to know the distance to the
marker can be done by measuring the distance between positions B
and C. It can reach the marker at last by vertically scanning from
the middle point of B and C, and even when misregistration can be
detected being caused in the scanned laser spot in the distance
from the middle point of B and C to the marker, and the position
gap is cruel, the marker finding can be done efficiently. In that
situation, if the laser spot came off from the backbone portion at
the previous scanning, reflectivity only has to shake the laser
spot to the right and left at the position which comes off once
though changes. Thus, it is possible to search for the middle point
in the direction of width of the backbone if the width of the
backbone at a position concerned can be recognized, and the
position gap can be corrected easily.
* * * * *